Taxonomy of the Chipmunks,
Eutamias quadrivittatus and Eutamias umbrinus

Capitalized color terms, which are used in descriptions and comparisons, are of Ridgway, "Color Standards and Color Nomenclature," Washington, D. C., 1912.

In the synonymy of each subspecies there appears only the first usage of a name, second the first usage of the name combination now employed unless a new combination is proposed by me, and third pure synonyms. The last is recognizable as such because the type locality is appended to each.

Unless otherwise specified, all specimens are in the Museum of Natural History, University of Kansas. The various collections of institutions and of private persons are indicated by the following symbols:

Of the external measurements, only the total length and the length of the tail are recorded in table 1. Some field collectors measured the ear from the notch and others from the crown; most collectors measured the length of the hind foot to the nearest millimeter rather than in tenths of a millimeter, as would have been desired. Consequently, I decided against using the lengths of the ear and hind foot in the study here reported on.

The measurements of the skull were made as shown in figure 1.

A total number of 434 specimens are listed as examined in this study, and additionally, numerous other specimens were superficially examined in the United States Biological Surveys Collection. Bacula of each of the named kinds of chipmunks in this paper, were examined.

Whenever two or more samples are stated to be significantly different, the meaning is that the difference is statistically significant.

The geographic distribution of each subspecies and the localities of specimens or series of specimens are plotted on the map (fig. 2).

When comparisons were made to ascertain specific and subspecific differences, only adults, or animals in which the enamel was worn through on the permanent P4 and p4 were used. Within this age range, only specimens in comparable pelage were used to ascertain differences in color.

Miss Viola S. Schantz of the United States Fish and Wildlife Service, Mr. Alfred Bailey of the Colorado Museum of Natural History, Dr. W. H. Burt of the Museum of Zoology of the University of Michigan, Dr. Stephen D. Durrant of the Museum of Zoology of the University of Utah, Dr. Robert M. Stabler, curator of the Warren Collection of Colorado College, and Mr. James S. Findley, generously loaned specimens for my use. Doctors E. Raymond Hall, Rollin H. Baker, Robert W. Wilson, Keith R. Kelson, E. Lendell Cockrum, and other friends and associates have given valued suggestions and assistance. My wife, Alice M. White, made the illustrations and helped me record and analyze the data.

Assistance with field work is acknowledged from the Kansas University Endowment Association, the National Science Foundation, and the United States Navy, Office of Naval Research, through contract No. NR161 791.